Lubricating oil composition



Unitc States, Patent 1cc LUBRICATING on. COMPOSITION Eugene'E. Richardson and Lawson W.- Mixon, Hammond,

Ind., assignors to Standard Oil Company, Chicago, 111.,

a corporation of Indiana No Drawing. Application June 30, 1955 Serial No. 519,259 I g 9 Claims. (Cl. 252- 32.7)

It has heretofore been discovered that certain reaction products of a phosphorus sulfide and a hydrocarbon, particularly an olefin or an olefin polymer, when added in small amounts to a hydrocarbon oil, are effective in inhibiting the formation of varnish, sludge,1 carbon and the like in lubricating oils during use. It has also been found that neutralizing these reaction products of a phosphorus sulfide and a hydrocarboriwith a' basic reagent such as a compound of barium provides-a composition which is effective as a detergent. However,it has since been found that under certain conditions lubricants containing such detergent do not provide sufficient rust proofing ability.

It is an object of this invention to provide a lubricant for internal combustion engines which will be effective in providing adequate lubrication for such engines. Another object of this invention is to provide alubricant additive which imparts improved rust proofing ability to the oil in addition to preventing the deterioration of the lubricant, acts as a detergent to prevent ring sticking, varnishing or coating of the metallic surfaces of the engines, and also functions as a suspending or dispersing agent for dispersing contaminating materials in the oil. Other objects and advantages of the invention will become apparent as the description thereof proceeds.

We have now discovered that a product having the desired rust proofing ability as well as improved carbon and/ or varnish inhibition properties and detergent prop erties can be obtained by incorporating in a lubricating oil a small amount such as from 0.001 to by Weight of a phosphorus, sulfur, and nitrogen-containing reaction product which is obtained by reacting a phosphorus sulfide with a hydrocarbon and then neutralizing the phosphorus sulfide-hydrocarbon reaction product with. a basic reagent containing a metal constituent, followed by reacting the neutralized product with NO (nitric oxide) or N 0 (nitrogen trioxide). The hydrocarbon reacted with the phosphorus sulfide may be an olefin polymer such as a butylene polymer. The phosphorus sulfide-hydrocarbon reaction product is neutralized by treating with a basic reagent containing a metal constituent, for example barium oxide or other alkali or alkaline earth metal oxides,

hydroxides, carbonates, or the like. The basic reagent used in neutralizing the phosphorussulfide hydrocarbon reaction product is preferably employed in an amount in"excess of that necessary to neutralize the phosphorus .Patented July 1,1958

- sulfide-hydrocarbon reaction product, thus producing-a product having excess basicity. Theneutralized product is reacted with NO orN O so as to introduce about 0.01]

and the effectiveness of mixing; The. preferred additive contains about 0510 5 moles, e. g. about '1 mole, of nitrogen' per mole of metal constituent, such as barium, which is contained in the neutralized phosphorous sulfide-by drocarbon reaction product. a I

As aforesaid, one of theicomponents of the proved lubricant is the neutralized reaction productof a hydrocarbon and a phosphorus sulfide such as P 8 P4S ,P Sr}, or other phosphorus sulfides, and preferably phosphorus pentasulfide, P 8 "The hydrocarbon constituent of this reaction is preferably a mono-olefin hydrocarbon poly-' 'mer resulting from the polymerization of low molecular Weight mono-olefinic hydrocarbons or isomono-olefin hydrocarbons such as propylenes, butylenes, and amylenes or the copolymers obtained by the polymerization of hydrocarbon mixtures containing isomono-olefins and mono-olefins of lessthan 6 carbon atoms. 'Ihe polymers may be obtained by the polymerization of these olefins or mixtures of olefins in'the' pres'ence of a catalyst such as sulfuric acid, phosphoric acid, boron fluoride, a1uminum chloride'or other similar halidecatalysts] of the 'Friedel- Crafts type. Thepolymers employed are preferably monorolefin polymers or mixtures of mono-olefin polymers and'isomonorolefin polymers having molecular weights ranging. from about 150 to about 50,000 or more, and preferably from about 500 to about 10,000. Such polymers can be obtained, for example, by the polymerization in the liquid phase of a hydrocarbon mixture containingmono-olefins and isomono-olefins such as butylene and isobutylene at a temperature of from about F. to about F.- in the presence of a metal halide catalyst of the Friedel- Crafts type such as, for example, boron fluoride, aluminum chloride and the like. In the preparation of these polymers we may employ, for example, a hydrocarbon .mixture containing isobutylene, butylenesand butanes recovered from'petroleum gases especially those gases produced in the cracking of petroleum oils -in the. man'u-.

facture of gasoline.-

A suitable polymer for the reaction with phosphorus sulfide is the product obtained by polymerizing in the. liquid phase ahydrocarbon mixture containing butylenes and isobutylenes together With .butanes and some C and C hydrocarbons at a temperature between about -0- F.- and 30 F. in the presence of aluminum chloride-LA suitable method for carrying out the.polymerizationis .to introduce the aluminum chloride into the reactorand introduce the hydrocarbon mixture cooled to a tempera ture of about 0 F. into the-"bottorn of the reactor and pass it upwardly through the catalyst layer while,regu-. lating the temperature within the reactorjso that the polymer product leaving the top ofjth'e reactor is at a seconds to about 2000 seconds Saybolt Universal at 210 F. V g V Another suitable polymer is .thatiobtained by polymer izing inthe liquid phase a hydrocarbonmixture comprising substantially C hydrocarbons in the presence of analuminum chloride-complex catalyst. The catalyst is preferably prepared by heating aluminum chloride with iso-octane. The hydrocarbon mixture is introduced into the bottom of the reactor and passed upwardly through the catalyst layer, while a temperature of from about 5 0 F. to about 110 F. is maintained in the reactor. The propane and other saturated gases pass through the catalyst, while the propylene is'polymerized under these conditions. The propylene polymer can be fractionated to any desired molecular weight, preferably from about 500 to about 1000 or higher. 7

Other suitable polymers can be obtained by polymerizing a hydrocarbon mixture containing about 10% to about isobutylene at-a temperature of from about 0 F. to about 100 F. and preferably 0 F. toabout 32 F. inthe presence of boron fluoride. After the polymerization of the isobutylene together with a relatively minor amount of the'norma'l olefins present, the reaction mass is neutralized, washed free of acidic substances and the unreacted hydrocarbons subsequently separated from the polymers by. distillation. The polymer mixture so obtained, depending upon the temperature of reaction, varies in consistency from a light liquid to viscous, oily material and contains polymers having molecular weights ranging from about 100 to about 2000 or higher. The polymers so obtained may be used as such, or the polymer may be fractionated under reduced pressure into fractions of increasing molecular weights, and suitable fractions reacted with the phosphorus sulfide to obtain the desired reaction products. The bottoms resulting from the fractionation of the polymer may have Saybolt Universal viscosities at 210 F. ranging from 50 seconds to about 10,000 seconds and'are well suited for the purpose of the present invention.

Essentially parafiinic hydrocarbons such as bright stock residuums, lubricating oil distillates, petrolatums, or paraffin Waxes may be used. There can also be employed the condensation products of any of the foregoing hydrocarbons, usually through first halogenating the hydrocarbons then reacting with aromatic hydrocarbons in the presence of anhydrous inorganic halides, such as aluminum chloride, zinc chloride, boron fluoride and the like.

Examples of high molecular weight olefinic hydrocarbons which can be employed as reactants are cetene (C cerotene (C melene (C and mixed high molecular alkenes obtained by cracking petroleum oils. Other preferred olefins suitable for the preparation of the herein-described phosphorus sulfide reaction products are olefins having at least 20 carbon atoms in the molecule of which from about 13 carbon atoms to about 18 carbon atoms, and preferably at least 15 carbon atoms, are in a long chain. Such olefins can be obtained by the dehydrogenation of parafiins, such as by the cracking of paraflin Waxes, or by the dehydrogenation of alkyl halides, preferably long chain alkyl halides, particularly halogenated parafiin waxes. g

The olefins obtained by dehydrohalogenation of long chain alkyl halides are preferably those obtained by dehydrohalogenation of monohalogenated waxes, such as for example, those obtained by dehydrochlo'rination of monochlor parafiin wax. The alkyl halides are decomposed to yield olefins according to, the reaction in which n is a whole numbeijpreferably 20 or more, and X is a halogen. It is preferred to employ paraffin waxes having at least about 20 carbon atoms per-molecule, and melting points upwards from about 90 F. to about To obtain the halogenated paraffin wax, for example, chlorinated paraffin wax, chlorine is introduced into the wax, maintained in a molten state, until the wax has a chlorine content of fromabout 8% to about. 15%. The chlorinated wax product is a mixture of unchlorinated wax, monochlor wax and polychlor wax. This chlorinated product may be used as such, but it is advantageous to use the substantially monochlor wax fraction. The monochlor wax fraction can be segregated from the unchlorinated wax and the polychlor wax fractions by taking advantage of the differences in the melting points of the various fractions, since the melting point of the wax varies with the extent of chlorination, i. e. the melting point of the unchlorinated wax is greater than that of the monochlor wax, and the melting point of the latter is greater than that of the polychlor wax. Thus, the monochlor parafiin wax can be separated from the unchlorinated and the polychlor wax fractions by means such as sweating, fractional distillation, solvent extraction, solvent precipitation, and fractional crystallization.

The high molecular weight olefins are obtained by removing the halogen as hydrogen halide from the halogenated parafiin wax. For example, the corresponding olefin is obtained from the monochlor parafiin wax by removing the chlorine from the latter as hydrogen chloride. The monochlor Wax can be dehydrochlorinated by heating to a temperature of from about 200 F. to about 600 F. in the presence of a dehydrochlorinating agent suchas an alkali metal hydroxide or an alkaline earth metal hydroxide or oxide Other alkaline inorganic or organic materials can also be used. The chlorine can also be removed from the chlorowax by heating the same for a prolonged period in the absenceof any dehydroclorinating agent. After the dehydrogenation has been completed the olefin so obtained can be further purified by removing the dehydrohalogenating agent by means of filtration or by other suitable'means.

As other. starting materials there can be used thepolymer or synthetic lubricating oil obtained by polymerizing unsaturated hydrocarbons, resulting from the vapor phase crackingof parafi'in waxes, in the presence of aluminum chloride, which is fully described in United States Patents Nos. 1,955,260, 1,970,402 and 2,091,398. Still another type of olefin polymer which may be employed is the polymer resulting from the treatment of vapor phase cracked gasolineand/or gasoline fractions with sulfuric acid or solid absorbents such as fullers earth whereby unsaturated polymerized hydrocarbons are removed. Also contemplated within the scope of this invention is the treatment with phosphorus sulfide of the polymers resulting from the voltolization of hydrocarbons as described, for example in United States Patents Nos. 2,197,768 and 2,191,787. a a

Also contemplated within the scope of the present invention are the reaction products of a phosphorus sulfide with an aromatic hydrocarbon such as for example benzene, naphthalene, toluene, xylene, diphenyl and the like, or with an alkylated aromatic hydrocarbon such as for example, benzene having an alkyl substituent having at least four carbon atoms and preferably at least eight carbon atoms such as for example, long chain parafiin waxes, olefin polymers and the like. V

.The phosphorus sulfide-hydrocarbon reaction product can be readily obtained by reacting a phosphorus sulfide, for example P 8 with the-hydrocarbon at a temperature of from about 200 F- to about 500 F. and preferably fromrabout 200 F. to about 400 F., usingfromfabout 1%. to about 50% .and preferably from about 5% to about 25% of the phosphorus sulfide in the reaction. It is advantageous to maintain a non-oxidizing atmosphere such as, for example, an atmosphere of nitrogen above the reaction mixture.,, Usually it is preferable to use an amount of'the phosphorus sulfide that will completely react with the hydrocarbon so that no further purification becomes necessaryghowever, an excess amount of phosphorus sulfide can be used and separated fromthe product by filtration or by dilution with a solvent such as hexane, filtering and subsequently removing the solvent by suitable means such as by distillation. If desired, the reaction product can be further treated an agent havin g an;

active hydrogenatomsuch as steam at an elevated temperature of from about 100 F. to about 600 F.

The phosphorus sulfide-hydrocarbon reaction .product normally shows a titratableacidity which is neutralized by treatment with a basic reagent. The phosphorus sulfidehydrocarbon reaction product when neutralized with a basic reagent'containing a metal constituent is characterized by the presence or retention of the metal constituent of the basic reagent. Other metal constituents such as a heavy metal constituent can be introduced into the neutralized product by reacting the same with a salt of the desired heavy metal. I

The term neutralized phosphorus sulfide-hydrocarbon reaction product as used herein means a phosphorus sulfide-hydrocarbon reaction product having at least about 1% of its titratable acidity neutralized by reaction with a basic reagent and includesthe neutralized phosphorus sulfide-hydrocarbon reaction products containing a inetal constituent resulting from said neutralization or resulting from the reaction of a heavy metal salt with the phosphorus sulfide-hydrocarbon reaction product-treated with a basic reagent. The term also includes those products which contain the metal constituent in excess of the amount stoichiometrically necessary to replace the acidic hydrogens of the acid compound. Such compounds have come to be known as having excess'basicity. They may conveniently be made by neutralizing with an amount of basic reagent in excess of that'necessary to replace the acidic hydrogens of the phosphorus sulfide-hydrocarbon reaction products. They are preferred for use in'this invention.

The neutralized phosphorus sulfide-hydrocarbon reaction product can be obtained by treating the reaction product with a suitable basic compound such as a hydroxide, carbonate, oxide or sulfide of an alkaline earth metal or an alkali metal such as, for example, potassium hydroxide, sodium hydroxide, sodium sulfide, etc. Other basic reagents can be used such as for example, ammonia or an alkylor aryl substituted ammonia such as amines. The neutralization of the phosphorus sulfide-hydrocarbon reaction product is carried out preferably in a non-oxidizing atmosphere by contacting the reaction product either as such or dissolved in a suitable solvent such as naphtha with a solution of the basic reagent, for example, potassium hydroxide or sodium hydroxide dissolved in alcohol. As an alternative method, the reaction product can be treated with solid alkaline compounds such as KOH, NaOH, Na CO K CO CaO, Na S, and the like at anelevated temperature of from about 100 F. to about 600 F. As was aforesaid, when the phosphorus sulfide-hydrocarbon reaction product is neutralized with a basic reagent containing a metal constituent, the neutralized reaction product is characterized by the presence of the metal constituent of the basic reagent. Neutralized reaction products containinga heavy. metal constituent such as, for example, tin, titanium, aluminum, chromium, cobalt, zinc, iron, and the like, can be obtained by reacting a salt of the desired heavy metal with the phosphorus sulfide-hydrocarbon reaction productiwhich has been treated with a basic reagent. It will'be understood that when the neutralization is accomplishedwith a polyvalent basic material such as lime, product havingexcess basicity may be obtained.

The phosphorus sulfide-hydrocarbon reaction product may be filtered, either before or after neutralization, with an absorbent material such as Attapulgus clay, Floridin, Filter Cel, Bentonite, Magnesite or similar diatomaceous earth materials. This treatment is described in detail in U. S. 2,688,612, issued to R. W. Watson on September 7, 1954.

The neutralized product is then reacted with a nitrogen oxide, specifically NO or N 0 It has been found that other nitrogen oxides such as N 0, N0 and N 0 are ineffective for improving the rust proofing properties of the finished additive. A convenient source of the desired nitrogen oxides is nitrous fumes containing predominantly NO and N 0 with a small amount of N0 which is pr'e= pared by reacting sulfuric acid with sodium mtrrte.

The neutralized phosphorus sulfide-hydrocarbon read tion product is reacted with NO or N 0 until about 0.01 to l0,'preferably about 0.5 to 5, moles of nitrogen are introduced per mole of the metal constituent which was introduced during the neutralization step. Thus a satis-.. factory additive contains about an equimolar ratio of; nitrogen to the metal constituent which was introduced during the neutralization step. The weight ratios will, of

course, vary depending upon the molecular weight of the metal constituent.

The method of introducing the proper amount of nitrogen into the additive is not critical. phosphorus sulfide-hydrocarbon reaction product may be treated at a temperature of about 50 to 400 -F., preferably between about to 200 F., with the oxide of nitrogen for about 0.1 to 24 hours, preferably about 0.5 to 5'hours. I

The time required will vary depending upon the effectiveness of contacting of the gas with the neutralized phosphorus sulfide-hydrocarbon reaction product and the rate at which the nitrogen oxide is being introduced into'the' reaction zone. Any unreacted oxide of nitrogen, as well as any moisture, may then be removed from the reaction product by blowing with an inert gas such as nitrogen or the like, for a time such as 0.1 to 2 hours.

The following example is illustrative of the herein is not intended as beingindicative f described invention and of the scope thereof.

' EXAMPLE I A butylene polymer having a molecular weight of about 800 was reacted with 16% P 8 at a temperature of about 450 F. and the reaction product diluted with The diluted an equal volume of an SAE-lO base oil. product was then hydrolyzed by treatment with steam at a temperature of about 300 F. The hydrolyzed product was then contacted with Attapulgus clay fines and the clay subsequently filtered 011' The filtered product was then sodium nitrite. The reaction mixture was then heated to 300? F. and blown with nitrogen for about one-half hour.

Residual absorbed but unreacted oxides of nitrogen as well as moisture were thus removed from the final additive. analysis by weight:

Percent P 1.28 S 0.43 Ba 7.06 N 0.54 N

A sample of the above additive and also a'sample of the neutralized phosphorus sulfide-butylenepolymer reaction product which had not been treated with an oxide I of. nitrogen were tested under' comparative conditions in the Static Drop Rust Test and also in the ASTM Rust- Preventing Characteristics in the Presence of Water Test (D-665). In each test 2.2 weight percent of the nitrogen oxide-treated neutralized phosphorus sulfide-olefin polymer reaction product, as well as the neutralized product which had not been reacted with the nitrogen oxide, were added to SAE-lO solvent extracted base oil along with 0.75 weight percent of sulfurized dipentene. The following table summarizes the results of the tests which compares the nitrogen oxide treated product with the product which had not been treated with an oxide of nitrogen.

The neutralized The neutralized product The additive so produced had the following product 1 As described by Baker et al. in Ind. Eng. Chem. 41, Jan. 1949, p. 137.

From the above results, it is apparent that treatment of the neutralized phosphorus sulfide-hydrocarbon reaction product with NO and/or N improves greatly the rust proofing ability of the additive. If the additive is not treated with the named oxides of nitrogen, then severe rusting which covers approximately al of the surface of the test specimen occurs, whereas when the additive has been treated with the named oxides of nitrogen the test specimen shows no evidence of rusting. The finished additive of this invention may usually be used in amount of from 0.001 to 15% by weight, preferably about 1 to by weight based upon lubricating oil. It is to be understood that concentrates of a suitable lubricating oil base containing from to about 50% or more of the additive of this invention can be used for blending with other lubricating oils in the proportion desired for the particular conditions of use to give a finished product containing the desired amount of the additive of this invention.

While the present invention has been described by the 0 use of the mixture of our composition in petroleum lubricating oils, other lubricating oil bases may be employed such as hydrocarbon oils, natural or synthetic, such as those obtained by the polymerization of olefins, as well as synthetic lubricating oils of the alkylene oxide types, and the polycarboxylic acid ester type oils such as the oilsoluble esters of adipic acid, sebacic acid, azelaic acid, etc.

Unless otherwise stated, the percentages stated herein and in the claims are weight percentages.

Although the present invention has been described with reference to specific preferred embodiments thereof, the invention is not to be considered as limited thereto, but includes within its scope such modifications and variations as come within the spirit of the appended claims.

We claim:

1. A lubricant composition comprising a major proportion of a lubricating oil and in combination therewith from about 0.001 to 15% by weight of a phosphorus, sulfur, and nitrogen-containing reaction product obtained by reacting a phosphorus sulfide at a temperature of about 200 to 500 F. with a hydrocarbon, subsequently neutralizing the phosphorus sulfide-hydrocarbon reaction product with a basic reagent containing a metal constituent, and then reacting said neutralized product with nitric oxide at a temperature of about 50 to 400 F.

2. A lubricant composition comprising a major proportion of a lubricating oil and in combination therewith from about 0.001 to 15% by weight of a phosphorus, sulfur, and nitrogen-containing reaction product obtained by reacting a phosphorus sulfide at a temperature of about 200 to 500 F. with an olefin polymer, subsequently neutralizing the phosphorus sulfide-olefin polymer reaction product with a basic reagent containing a me tal constituent, and then reacting said neutralized productwith' nitric oxide at a temperature of about 50 to 400 3. The composition of claim 2 wherein said olefin polymer is a butylene polymer. 7 H i ,4. The composition of claim 2 wherein said phosphorus sulfide is P 8 1 5. The composition of claim 2 stituent is barium. v 6. The composition of claim 2 wherein said phosphorus sulfide-olefin polymer reaction product is treated with an amount of basic reagent in excess of that necessary to neutralize said phosphorus sulfide-olefin polymer reaction product. H I 7. The composition of claim 2 wherein said'neutralized product is reacted with said nitric oxidewherebyfrom about 0.01 to 10 moles of nitrogen are introduced per mole of metal constituent contained in said phosphorus sulfide-olefin polymer reaction product;

8. A lubricant composition comprising a major proportion of a lubricating oil and in combination therewith from about 0.001 to 15 by weight of a phosphorus,

sulfur, and nitrogen-containing reaction product obtained by reacting a phosphorus sulfide at a temperature of about.

200 to 500 F. with a butylene polymer, subsequently neutralizing the phosphorus sulfidebutylene polym'er reaction product by treatment thereof with an amount'ot basic reagent in excess of that necessary to neutralize said phosphorus sulfide-butylene polymer reaction product, said basic reagent containing barium as a metalconstituent, reacting said neutralized product .with nitric oxide at a temperature of about 50. to 400 F. whereby from about 0.1 'to 5 moles of. nitrogen are incorporated in said neutralized product per mole of barium contained therein. i

9. A concentrated solution of a lubricating oil additive comprising from about to 50% of a lubricating oil and from about 15 to 50% of a detergent type additive having improved rust proofing properties which is prepared by reacting a phosphorous sulfide with a butylene polymer at a temperature of'from about 200 to 500 F., subsequently neutralizing the' phosphorous sulfide-butylene polymer reaction product by' treatment thereof with an amount of basic reagent in excess of that necessary to neutralize said phosphorous sulfidebutylene polymer reaction product, said basic reagent containing barium as the metal constituent, reacting said neutralized product at a temperature between about 50 and 400 F. with nitric oxide whereby from about 0.1 to 5 mols of nitrogen are incorporated in'said neutral ized product per mol of barium contained thereii1;- said concentrated solution of additive being capable of dilu-; tion with a major proportion of'a lubricating oil to form a lubricant composition comprised of a major proportion of lubricating oil and from of the additive.

References Cited in the fil'e'of this patent UNITED STATES PATENTS 2,691,002 Bartleson Oct. 5,; 1954 wherein metal conabout 0.001 to 15% by weight 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PROPORTION OF A LUBRICATING OIL AND IN COMBINATION THEREWITH FROM ABOUT 0.001 TO 15% BY WEIGHT OF A PHOSPHORUS, SULFUR, AND NITROGEN-CONTAINING REACTION PRODUCT OBTAINED BY REACTING A PHOSPHORUS SULFIDE AT A TEMPERATURE OF ABOUT 200* TO 500*F. WITH A HYDROCARBON SUBSEQUENTLY NEUTRALIZING THE PHOSPHORUS SULFIDE-HYDROCARBON RECTION PRODUCT WITH A BASIC REAGENT CONTAINING A METAL CONSTITUENT, AND THEN REACTING SAID NEUTRALIZED PRODUCT WITH NITRIC OXIDE AT A TEMPERATURE OF ABOUT 50* TO 400*F. 